Fluorescence Filters: Essential Components for Precision Imaging
Fluorescence filters are critical components in fluorescence microscopy, consisting of three key elements: Excitation Filter (EX), Dichroic Mirror (DM), and Emission Filter (EM). A high-quality filter set effectively blocks stray light, ensuring pure and sharp fluorescence imaging. The performance of these filters is heavily dependent on coating technology—optimized thin-film deposition enhances light transmittance while minimizing unwanted reflections. OPTOStokes integrates these components into high-efficiency filter cubes, delivering superior light throughput and imaging clarity.
How Fluorescence Filters Work
Typically constructed using optically clear glass substrates, fluorescence filters utilize thin-film coatings on both surfaces to control light transmission and reflection. Anti-reflective (AR) coatings—with thicknesses designed as quarter-wavelength multiples—maximize light passage at target wavelengths. In contrast, high-reflective (HR) coatings use half-wavelength thicknesses to enhance reflection through constructive interference.
In practical applications, these filters function as integrated systems (filter cubes):
- Excitation Filter (EX): Transmits specific excitation wavelengths while blocking ambient light in the emission band
- Dichroic Mirror (DM): Reflects excitation light toward the sample while transmitting emitted fluorescence
- Emission Filter (EM): Further isolates fluorescence signals by blocking residual excitation light
Key Features of High-Quality Fluorescence Filters
1. Optical Performance Metrics
- Low stray light: Precise alignment with fluorophore excitation/emission peaks (≤5% cross-talk)
- Deep blocking: Optical Density (OD) ≥6 to minimize background noise
- Low auto-fluorescence: Substrate and coatings designed to avoid self-emission interference
2. Mechanical Precision
Surface flatness directly impacts imaging quality. Transmission Wavefront Distortion (TWD) is strictly controlled—typically ≤λ/4 at 633nm—per ISO 10110 standards to prevent focal shifts or image distortion.
OPTOStokes Fluorescence Filter Solutions
Custom Filters for Specialized Applications
Tailored for advanced techniques like FISH (Fluorescence In Situ Hybridization), these filters optimize signal-to-noise ratios:
| Model | Excitation (EX) | Dichroic (DM) | Emission (EM) | Application |
|---|---|---|---|---|
| Blue B2 | 450/50 | 485 | 495LP | Tuberculosis detection |
| Violet V | 405/30 | 440 | 450LP | Stereomicroscopy accessories |
| Yellow G2 | 560/40 | 600 | 610LP | Enhanced Y-channel imaging |
| Red R | 620/50 | 655 | 692/45 | CY5 & near-IR dyes |
| Dual-pass B/G | 470/40 & 575/35 | - | 525/40 & 625/60 | FISH projects |
Standard Filters for Common Wavelengths
OPTOStokes offers BGUY series filters in longpass and bandpass configurations:
| Type | Excitation (EX) | Dichroic (DM) | Emission (EM) |
|---|---|---|---|
| UV Longpass U | 330-385nm | 410 | 420LP |
| UV Bandpass U | 330-390nm | 415 | 435-485nm |
| Blue Longpass B | 460-495nm | 505 | 510LP |
| Blue Bandpass B | 460-495nm | 505 | 510-550nm |
| Green Longpass G | 510-555nm | 570 | 575LP |
| Green Bandpass G | 528-553nm | 565 | 578-633nm |
Compatible Filter Cubes
OPTOStokes provides empty filter cubes compatible with major microscopy brands, including LEICA, OLYMPUS, ZEISS, and NIKON. These cubes can be pre-assembled with our fluorescence filters for plug-and-play integration, ensuring precise alignment and optimal performance.
Why Choose OPTOStokes Fluorescence Filters?
Whether you need standard configurations or custom solutions for specialized assays, OPTOStokes delivers: Extensive ready-to-ship inventory for rapid deployment, and custom coating services meeting international quality standards. Our complete production lines ensure consistent performance and controllable lead times.
For microscopy setups requiring precise fluorescence filtering—from routine lab work to advanced FISH analysis—contact sales@optofilters.com or leave a message to discuss your specific requirements.
